Not able to fund Agreement

I have defined contract type project and attached 2 customer at Project level, for one of the customer i have checked the Default Top Task Customer at Project level

at Project Type setup Funding Level Both is selected

i am not able fund the Agreement for the customer for which Default Top Task Customer check box is selected and system is giving an Error Project Level Funding Is Not Allowed Because Task Level Funding Exists APP-PA-19165 , i read the metalink note Doc ID 290070.1

so is there way to fund the agreement for this customer ? please advise

I am able to fund the agreement for other customer for which Default Top Task Customer check box is not selected